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Microsoft today released updates to fix at least 90 security vulnerabilities in Windows and related software, including a whopping six zero-day flaws that are already being actively exploited by attackers.
Image: Shutterstock.
This month’s bundle of update joy from Redmond includes patches for security holes in Office, .NET, Visual Studio, Azure, Co-Pilot, Microsoft Dynamics, Teams, Secure Boot, and of course Windows itself. Of the six zero-day weaknesses Microsoft addressed this month, half are local privilege escalation vulnerabilities — meaning they are primarily useful for attackers when combined with other flaws or access.
CVE-2024-38106, CVE-2024-38107 and CVE-2024-38193 all allow an attacker to gain SYSTEM level privileges on a vulnerable machine, although the vulnerabilities reside in different parts of the Windows operating system.
Microsoft’s advisories include little information about the last two privilege escalation flaws, other than to note they are being actively exploited. Microsoft says CVE-2024-38106 exists in the Windows Kernel and is being actively exploited, but that it has a high “attack complexity,” meaning it can be tricky for malware or miscreants to exploit reliably.
“Microsoft lists exploit complexity as high due to the attacker needing to win a race condition,” Trend Micro’s ZeroDay Initiative (ZDI) noted. “However, some races are easier to run than others. It’s times like this where the CVSS can be misleading. Race conditions do lead to complexity high in the CVSS score, but with attacks in the wild, it’s clear this bug is readily exploitable.”
Another zero-day this month is CVE-2024-38178, a remote code execution flaw that exists when the built-in Windows Edge browser is operating in “Internet Explorer Mode.” IE mode is not on by default in Edge, but it can be enabled to work with older websites or applications that aren’t supported by modern Chromium-based browsers.
“While this is not the default mode for most users, this exploit being actively exploited suggests that there are occasions in which the attacker can set this or has identified an organization (or user) that has this configuration,” wrote Kev Breen, senior director of threat research at Immersive Labs.
CVE-2024-38213 is a zero-day flaw that allows malware to bypass the “Mark of the Web,” a security feature in Windows that marks files downloaded from the Internet as untrusted (this Windows Smartscreen feature is responsible for the “Windows protected your PC” popup that appears when opening files downloaded from the Web).
“This vulnerability is not exploitable on its own and is typically seen as part of an exploit chain, for example, modifying a malicious document or exe file to include this bypass before sending the file via email or distributing on compromised websites,” Breen said.
The final zero-day this month is CVE-2024-38189, a remote code execution flaw in Microsoft Project. However, Microsoft and multiple security firms point out that this vulnerability only works on customers who have already disabled notifications about the security risks of running VBA Macros in Microsoft Project (not the best idea, as malware has a long history of hiding within malicious Office Macros).
Separately, Adobe today released 11 security bulletins addressing at least 71 security vulnerabilities across a range of products, including Adobe Illustrator, Dimension, Photoshop, InDesign, Acrobat and Reader, Bridge, Substance 3D Stager, Commerce, InCopy, and Substance 3D Sampler/Substance 3D Designer. Adobe says it is not aware of active exploitation against any of the flaws it fixed this week.
It’s a good idea for Windows users to stay current with security updates from Microsoft, which can quickly pile up otherwise. That doesn’t mean you have to install them on Patch Tuesday each month. Indeed, waiting a day or three before updating is a sane response, given that sometimes updates go awry and usually within a few days Microsoft has fixed any issues with its patches. It’s also smart to back up your data and/or image your Windows drive before applying new updates.
For a more detailed breakdown of the individual flaws addressed by Microsoft today, check out the SANS Internet Storm Center’s list. For those admins responsible for maintaining larger Windows environments, it pays to keep an eye on Askwoody.com, which frequently points out when specific Microsoft updates are creating problems for a number of users.
If only Patch Tuesdays came around infrequently — like total solar eclipse rare — instead of just creeping up on us each month like The Man in the Moon. Although to be fair, it would be tough for Microsoft to eclipse the number of vulnerabilities fixed in this month’s patch batch — a record 147 flaws in Windows and related software.
Yes, you read that right. Microsoft today released updates to address 147 security holes in Windows, Office, Azure, .NET Framework, Visual Studio, SQL Server, DNS Server, Windows Defender, Bitlocker, and Windows Secure Boot.
“This is the largest release from Microsoft this year and the largest since at least 2017,” said Dustin Childs, from Trend Micro’s Zero Day Initiative (ZDI). “As far as I can tell, it’s the largest Patch Tuesday release from Microsoft of all time.”
Tempering the sheer volume of this month’s patches is the middling severity of many of the bugs. Only three of April’s vulnerabilities earned Microsoft’s most-dire “critical” rating, meaning they can be abused by malware or malcontents to take remote control over unpatched systems with no help from users.
Most of the flaws that Microsoft deems “more likely to be exploited” this month are marked as “important,” which usually involve bugs that require a bit more user interaction (social engineering) but which nevertheless can result in system security bypass, compromise, and the theft of critical assets.
Ben McCarthy, lead cyber security engineer at Immersive Labs called attention to CVE-2024-20670, an Outlook for Windows spoofing vulnerability described as being easy to exploit. It involves convincing a user to click on a malicious link in an email, which can then steal the user’s password hash and authenticate as the user in another Microsoft service.
Another interesting bug McCarthy pointed to is CVE-2024-29063, which involves hard-coded credentials in Azure’s search backend infrastructure that could be gleaned by taking advantage of Azure AI search.
“This along with many other AI attacks in recent news shows a potential new attack surface that we are just learning how to mitigate against,” McCarthy said. “Microsoft has updated their backend and notified any customers who have been affected by the credential leakage.”
CVE-2024-29988 is a weakness that allows attackers to bypass Windows SmartScreen, a technology Microsoft designed to provide additional protections for end users against phishing and malware attacks. Childs said one of ZDI’s researchers found this vulnerability being exploited in the wild, although Microsoft doesn’t currently list CVE-2024-29988 as being exploited.
“I would treat this as in the wild until Microsoft clarifies,” Childs said. “The bug itself acts much like CVE-2024-21412 – a [zero-day threat from February] that bypassed the Mark of the Web feature and allows malware to execute on a target system. Threat actors are sending exploits in a zipped file to evade EDR/NDR detection and then using this bug (and others) to bypass Mark of the Web.”
Update, 7:46 p.m. ET: A previous version of this story said there were no zero-day vulnerabilities fixed this month. BleepingComputer reports that Microsoft has since confirmed that there are actually two zero-days. One is the flaw Childs just mentioned (CVE-2024-21412), and the other is CVE-2024-26234, described as a “proxy driver spoofing” weakness.
Satnam Narang at Tenable notes that this month’s release includes fixes for two dozen flaws in Windows Secure Boot, the majority of which are considered “Exploitation Less Likely” according to Microsoft.
“However, the last time Microsoft patched a flaw in Windows Secure Boot in May 2023 had a notable impact as it was exploited in the wild and linked to the BlackLotus UEFI bootkit, which was sold on dark web forums for $5,000,” Narang said. “BlackLotus can bypass functionality called secure boot, which is designed to block malware from being able to load when booting up. While none of these Secure Boot vulnerabilities addressed this month were exploited in the wild, they serve as a reminder that flaws in Secure Boot persist, and we could see more malicious activity related to Secure Boot in the future.”
For links to individual security advisories indexed by severity, check out ZDI’s blog and the Patch Tuesday post from the SANS Internet Storm Center. Please consider backing up your data or your drive before updating, and drop a note in the comments here if you experience any issues applying these fixes.
Adobe today released nine patches tackling at least two dozen vulnerabilities in a range of software products, including Adobe After Effects, Photoshop, Commerce, InDesign, Experience Manager, Media Encoder, Bridge, Illustrator, and Adobe Animate.
KrebsOnSecurity needs to correct the record on a point mentioned at the end of March’s “Fat Patch Tuesday” post, which looked at new AI capabilities built into Adobe Acrobat that are turned on by default. Adobe has since clarified that its apps won’t use AI to auto-scan your documents, as the original language in its FAQ suggested.
“In practice, no document scanning or analysis occurs unless a user actively engages with the AI features by agreeing to the terms, opening a document, and selecting the AI Assistant or generative summary buttons for that specific document,” Adobe said earlier this month.
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We learned some remarkable new details this week about the recent supply-chain attack on VoIP software provider 3CX. The lengthy, complex intrusion has all the makings of a cyberpunk spy novel: North Korean hackers using legions of fake executive accounts on LinkedIn to lure people into opening malware disguised as a job offer; malware targeting Mac and Linux users working at defense and cryptocurrency firms; and software supply-chain attacks nested within earlier supply chain attacks.
Researchers at ESET say this job offer from a phony HSBC recruiter on LinkedIn was North Korean malware masquerading as a PDF file.
In late March 2023, 3CX disclosed that its desktop applications for both Windows and macOS were compromised with malicious code that gave attackers the ability to download and run code on all machines where the app was installed. 3CX says it has more than 600,000 customers and 12 million users in a broad range of industries, including aerospace, healthcare and hospitality.
3CX hired incident response firm Mandiant, which released a report on Wednesday that said the compromise began in 2022 when a 3CX employee installed a malware-laced software package distributed via an earlier software supply chain compromise that began with a tampered installer for X_TRADER, a software package provided by Trading Technologies.
“This is the first time Mandiant has seen a software supply chain attack lead to another software supply chain attack,” reads the April 20 Mandiant report.
Mandiant found the earliest evidence of compromise uncovered within 3CX’s network was through the VPN using the employee’s corporate credentials, two days after the employee’s personal computer was compromised.
“Eventually, the threat actor was able to compromise both the Windows and macOS build environments,” 3CX said in an April 20 update on their blog.
Mandiant concluded that the 3CX attack was orchestrated by the North Korean state-sponsored hacking group known as Lazarus, a determination that was independently reached earlier by researchers at Kaspersky Lab and Elastic Security.
Mandiant found the compromised 3CX software would download malware that sought out new instructions by consulting encrypted icon files hosted on GitHub. The decrypted icon files revealed the location of the malware’s control server, which was then queried for a third stage of the malware compromise — a password stealing program dubbed ICONICSTEALER.
The double supply chain compromise that led to malware being pushed out to some 3CX customers. Image: Mandiant.
Meanwhile, the security firm ESET today published research showing remarkable similarities between the malware used in the 3CX supply chain attack and Linux-based malware that was recently deployed via fake job offers from phony executive profiles on LinkedIn. The researchers said this was the first time Lazarus had been spotted deploying malware aimed at Linux users.
As reported in a series last summer here, LinkedIn has been inundated this past year by fake executive profiles for people supposedly employed at a range of technology, defense, energy and financial companies. In many cases, the phony profiles spoofed chief information security officers at major corporations, and some attracted quite a few connections before their accounts were terminated.
Mandiant, Proofpoint and other experts say Lazarus has long used these bogus LinkedIn profiles to lure targets into opening a malware-laced document that is often disguised as a job offer. This ongoing North Korean espionage campaign using LinkedIn was first documented in August 2020 by ClearSky Security, which said the Lazarus group operates dozens of researchers and intelligence personnel to maintain the campaign globally.
Microsoft Corp., which owns LinkedIn, said in September 2022 that it had detected a wide range of social engineering campaigns using a proliferation of phony LinkedIn accounts. Microsoft said the accounts were used to impersonate recruiters at technology, defense and media companies, and to entice people into opening a malicious file. Microsoft found the attackers often disguised their malware as legitimate open-source software like Sumatra PDF and the SSH client Putty.
Microsoft attributed those attacks to North Korea’s Lazarus hacking group, although they’ve traditionally referred to this group as “ZINC“. That is, until earlier this month, when Redmond completely revamped the way it names threat groups; Microsoft now references ZINC as “Diamond Sleet.”
The ESET researchers said they found a new fake job lure tied to an ongoing Lazarus campaign on LinkedIn designed to compromise Linux operating systems. The malware was found inside of a document that offered an employment contract at the multinational bank HSBC.
“A few weeks ago, a native Linux payload was found on VirusTotal with an HSBC-themed PDF lure,” wrote ESET researchers Peter Kalnai and Marc-Etienne M.Leveille. “This completes Lazarus’s ability to target all major desktop operating systems. In this case, we were able to reconstruct the full chain, from the ZIP file that delivers a fake HSBC job offer as a decoy, up until the final payload.”
ESET said the malicious PDF file used in the scheme appeared to have a file extension of “.pdf,” but that this was a ruse. ESET discovered that the dot in the filename wasn’t a normal period but instead a Unicode character (U+2024) representing a “leader dot,” which is often used in tables of contents to connect section headings with the page numbers on which those sections begin.
“The use of the leader dot in the filename was probably an attempt to trick the file manager into treating the file as an executable instead of a PDF,” the researchers continued. “This could cause the file to run when double-clicked instead of opening it with a PDF viewer.”
ESET said anyone who opened the file would see a decoy PDF with a job offer from HSBC, but in the background the executable file would download additional malware payloads. The ESET team also found the malware was able to manipulate the program icon displayed by the malicious PDF, possibly because fiddling with the file extension could cause the user’s system to display a blank icon for the malware lure.
Kim Zetter, a veteran Wired.com reporter and now independent security journalist, interviewed Mandiant researchers who said they expect “many more victims” will be discovered among the customers of Trading Technologies and 3CX now that news of the compromised software programs is public.
“Mandiant informed Trading Technologies on April 11 that its X_Trader software had been compromised, but the software maker says it has not had time to investigate and verify Mandiant’s assertions,” Zetter wrote in her Zero Day newsletter on Substack. For now, it remains unclear whether the compromised X_Trader software was downloaded by people at other software firms.
If there’s a silver lining here, the X_Trader software had been decommissioned in April 2020 — two years before the hackers allegedly embedded malware in it.
“The company hadn’t released new versions of the software since that time and had stopped providing support for the product, making it a less-than-ideal vector for the North Korean hackers to infect customers,” Zetter wrote.
Microsoft today released software updates to plug 100 security holes in its Windows operating systems and other software, including a zero-day vulnerability that is already being used in active attacks. Not to be outdone, Apple has released a set of important updates addressing two zero-day vulnerabilities that are being used to attack iPhones, iPads and Macs.
On April 7, Apple issued emergency security updates to fix two weaknesses that are being actively exploited, including CVE-2023-28206, which can be exploited by apps to seize control over a device. CVE-2023-28205 can be used by a malicious or hacked website to install code.
Both vulnerabilities are addressed in iOS/iPadOS 16.4.1, iOS 15.7.5, and macOS 12.6.5 and 11.7.6. If you use Apple devices and you don’t have automatic updates enabled (they are on by default), you should probably take care of that soon as detailed instructions on how to attack CVE-2023-28206 are now public.
Microsoft’s bevy of 100 security updates released today include CVE-2023-28252, which is a weakness in Windows that Redmond says is under active attack. The vulnerability is in the Windows Common Log System File System (CLFS) driver, a core Windows component that was the source of attacks targeting a different zero-day vulnerability in February 2023.
“If it seems familiar, that’s because there was a similar 0-day patched in the same component just two months ago,” said Dustin Childs at the Trend Micro Zero Day Initiative. “To me, that implies the original fix was insufficient and attackers have found a method to bypass that fix. As in February, there is no information about how widespread these attacks may be. This type of exploit is typically paired with a code execution bug to spread malware or ransomware.”
According to the security firm Qualys, this vulnerability has been leveraged by cyber criminals to deploy Nokoyawa ransomware.
“This is a relatively new strain for which there is some open source intel to suggest that it is possibly related to Hive ransomware – one of the most notable ransomware families of 2021 and linked to breaches of over 300+ organizations in a matter of just a few months,” said Bharat Jogi, director of vulnerability and threat research at Qualys.
Jogi said while it is still unclear which exact threat actor is targeting CVE-2023-28252, targets have been observed in South and North America, regions across Asia and at organizations in the Middle East.
Satnam Narang at Tenable notes that CVE-2023-28252 is also the second CLFS zero-day disclosed to Microsoft by researchers from Mandiant and DBAPPSecurity (CVE-2022-37969), though it is unclear if both of these discoveries are related to the same attacker.
Seven of the 100 vulnerabilities Microsoft fixed today are rated “Critical,” meaning they can be used to install malicious code with no help from the user. Ninety of the flaws earned Redmond’s slightly less-dire “Important” label, which refers to weaknesses that can be used to undermine the security of the system but which may require some amount of user interaction.
Narang said Microsoft has rated nearly 90% of this month’s vulnerabilities as “Exploitation Less Likely,” while just 9.3% of flaws were rated as “Exploitation More Likely.” Kevin Breen at Immersive Labs zeroed in on several notable flaws in that 9.3%, including CVE-2023-28231, a remote code execution vulnerability in a core Windows network process (DHCP) with a CVSS score of 8.8.
“‘Exploitation more likely’ means it’s not being actively exploited but adversaries may look to try and weaponize this one,” Breen said. “Micorosft does note that successful exploitation requires an attacker to have already gained initial access to the network. This could be via social engineering, spear phishing attacks, or exploitation of other services.”
Breen also called attention to CVE-2023-28220 and CVE-2023-28219 — a pair of remote code execution vulnerabilities affecting Windows Remote Access Servers (RAS) that also earned Microsoft’s “exploitation more likely” label.
“An attacker can exploit this vulnerability by sending a specially crafted connection request to a RAS server, which could lead to remote code execution,” Breen said. While not standard in all organizations, RAS servers typically have direct access from the Internet where most users and services are connected. This makes it extremely enticing for attackers as they don’t need to socially engineer their way into an organization. They can simply scan the internet for RAS servers and automate the exploitation of vulnerable devices.”
For more details on the updates released today, see the SANS Internet Storm Center roundup. If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.
Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any problems as a result of these patches.
Microsoft on Tuesday released updates to quash at least 74 security bugs in its Windows operating systems and software. Two of those flaws are already being actively attacked, including an especially severe weakness in Microsoft Outlook that can be exploited without any user interaction.
The Outlook vulnerability (CVE-2023-23397) affects all versions of Microsoft Outlook from 2013 to the newest. Microsoft said it has seen evidence that attackers are exploiting this flaw, which can be done without any user interaction by sending a booby-trapped email that triggers automatically when retrieved by the email server — before the email is even viewed in the Preview Pane.
While CVE-2023-23397 is labeled as an “Elevation of Privilege” vulnerability, that label doesn’t accurately reflect its severity, said Kevin Breen, director of cyber threat research at Immersive Labs.
Known as an NTLM relay attack, it allows an attacker to get someone’s NTLM hash [Windows account password] and use it in an attack commonly referred to as “Pass The Hash.”
“The vulnerability effectively lets the attacker authenticate as a trusted individual without having to know the person’s password,” Breen said. “This is on par with an attacker having a valid password with access to an organization’s systems.”
Security firm Rapid7 points out that this bug affects self-hosted versions of Outlook like Microsoft 365 Apps for Enterprise, but Microsoft-hosted online services like Microsoft 365 are not vulnerable.
The other zero-day flaw being actively exploited in the wild — CVE-2023-24880 — is a “Security Feature Bypass” in Windows SmartScreen, part of Microsoft’s slate of endpoint protection tools.
Patch management vendor Action1 notes that the exploit for this bug is low in complexity and requires no special privileges. But it does require some user interaction, and can’t be used to gain access to private information or privileges. However, the flaw can allow other malicious code to run without being detected by SmartScreen reputation checks.
Dustin Childs, head of threat awareness at Trend Micro’s Zero Day Initiative, said CVE-2023-24880 allows attackers to create files that would bypass Mark of the Web (MOTW) defenses.
“Protective measures like SmartScreen and Protected View in Microsoft Office rely on MOTW, so bypassing these makes it easier for threat actors to spread malware via crafted documents and other infected files that would otherwise be stopped by SmartScreen,” Childs said.
Seven other vulnerabilities Microsoft patched this week earned its most-dire “critical” severity label, meaning the updates address security holes that could be exploited to give the attacker full, remote control over a Windows host with little or no interaction from the user.
Also this week, Adobe released eight patches addressing a whopping 105 security holes across a variety of products, including Adobe Photoshop, Cold Fusion, Experience Manager, Dimension, Commerce, Magento, Substance 3D Stager, Cloud Desktop Application, and Illustrator.
For a more granular rundown on the updates released today, see the SANS Internet Storm Center roundup. If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.
Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any problems as a result of these patches.
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